//
//  GaodeTransform.m
//  Hive
//
//  Created by 惠俊贝 on 15/9/1.
//  Copyright (c) 2015年 ZM. All rights reserved.
//

#import "GaodeTransform.h"
#import "LonLat.h"

static const double pi = 3.14159265358979324;
static const double a = 6378245.0;  //地球半径
static const double ee = 0.00669342162296594323;
@interface GaodeTransform () {
    
}
+ (BOOL)outOfChina:(double)lat :(double)lon;
+ (double)transformLat:(double)x :(double)y;
+ (double)transformLon:(double)x :(double)y;
@end

@implementation GaodeTransform


+ (LonLat *)transform:(double)wgLat :(double)wgLon {
    LonLat *aLonlat = [[LonLat alloc] init];
    if ([self outOfChina:wgLat :wgLon]) {
        aLonlat.lat = wgLat;
        aLonlat.lon = wgLon;
    }
    else {
        double dLat =[self transformLat:wgLon - 105.0 :wgLat - 35.0];
        double dLon =[self transformLon:wgLon - 105.0 :wgLat - 35.0];
        double radLat = wgLat / 180.0 * pi;
        double magic = sin(radLat);
        magic = 1 - ee * magic * magic;
        double sqrtMagic = sqrt(magic);
        dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
        dLon = (dLon * 180.0) / (a / sqrtMagic * cos(radLat) * pi);
        aLonlat.lat = wgLat + dLat;
        aLonlat.lon = wgLon + dLon;  //精确到小数点后7位
    }
    return  aLonlat;
}

+ (BOOL)outOfChina:(double)lat :(double)lon {
    if (lon < 72.004 || lon > 137.8347) {
        return YES;
    }
    if (lat < 0.8293 || lat > 55.8271) {
        return YES;
    }
    return NO;
}

+ (double)transformLat:(double)x :(double)y {

    double ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * sqrt(fabs(x));
    ret += (20.0 * sin(6.0 * x * pi) + 20.0 * sin(2.0 * x * pi)) * 2.0 / 3.0;
    ret += (20.0 * sin(y * pi) + 40.0 * sin(y / 3.0 * pi)) * 2.0 / 3.0;
    ret += (160.0 * sin(y / 12.0 * pi) + 320 * sin(y * pi / 30.0)) * 2.0 / 3.0;
    return ret;
}
+ (double)transformLon:(double)x :(double)y {
    double ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * sqrt(fabs(x));
    ret += (20.0 * sin(6.0 * x * pi) + 20.0 * sin(2.0 * x * pi)) * 2.0 / 3.0;
    ret += (20.0 * sin(x * pi) + 40.0 * sin(x / 3.0 * pi)) * 2.0 / 3.0;
    ret += (150.0 * sin(x / 12.0 * pi) + 300.0 * sin(x / 30.0 * pi)) * 2.0 / 3.0;
    return ret;
}
@end
